1. Field of the Invention
The present invention relates to an image processing apparatus for performing image processing on an image and an image processing method thereof.
2. Description of the Related Art
Generally in an image processing system, when a new image is created by performing various image processing on an image, an image processing parameter must be set for each image processing operation. In this case, when image processing parameters are not appropriately set, an image desired by an operator cannot be obtained. More particularly, in image processing of an X-ray image, image processing parameters that are most effective for diagnosis must be set. However, it is very difficult to set such image processing parameters.
In order to obtain better images, it is necessary to perform so many image processing operations. Thus, the number of combinations of image processing parameters used at that time is large. In addition, it takes very long time to obtain a desired parameter from among the large number of combinations of the image processing parameters through trial and error. Thus, the work is very hard for an operator.
To solve such a problem, for example, Japanese Patent Publication Nos. 7-43773 and 7-104914 discuss conventional techniques for creating and presenting some sample images on which image processing is preliminarily performed, and for selecting one of the presented sample images. According to the conventional techniques, sample images on which complex image processing is preliminarily performed are presented. Thus, even when an operator does not concretely know about the image processing at all, the operator can set appropriate image processing parameters by selecting one of the presented sample images, which is closest to an image to be obtained.
However, images to be desired by an operator can include various images. According to the conventional techniques, a sample image that is exactly matched with an image desired by an operator is not necessarily prepared.
At that time, when all images assumed to be desired by an operator are prepared, image processing corresponding to each of all combinations of image processing parameters should be performed. Thus, the number of sample images to be prepared is huge. In this case, an operator should perform very troublesome operations in order to select an image from a huge number of sample images. Consequently, the work by an operator is increased.
More particularly, for an X-ray image, image processing parameters are set for obtaining an X-ray image suitable for diagnosis. However, an X-ray image to be processed changes based on photographing conditions for photographing the X-ray image. Accordingly, for an X-ray image, it is necessary to change photographing conditions together with image processing parameters set suitable for diagnosis.
There are the following limiting conditions for an X-ray image to be used for diagnosis. One limiting condition is that whoever patients are examined, a density of an X-ray image at a specific position of a patient to be examined must be substantially similar to a density of an X-ray image at the similar position of other patients to be examined. Another limiting condition is that sufficient contrast must be obtained over the entire image of a patient. However, if image processing parameters are simply changed, the limiting conditions cannot be satisfied.
The present invention is accomplished in view of the above problems.